Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4904 insertions, 0 deletions

diff --git a/src/boost/libs/asio/test/write.cpp b/src/boost/libs/asio/test/write.cpp
new file mode 100644
index 00000000..758ab2a8
--- /dev/null
+++ b/src/boost/libs/asio/test/write.cpp
@@ -0,0 +1,4904 @@
+//
+// write.cpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+// Disable autolinking for unit tests.
+#if !defined(BOOST_ALL_NO_LIB)
+#define BOOST_ALL_NO_LIB 1
+#endif // !defined(BOOST_ALL_NO_LIB)
+
+// Test that header file is self-contained.
+#include <boost/asio/write.hpp>
+
+#include <cstring>
+#include <vector>
+#include "archetypes/async_result.hpp"
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/asio/streambuf.hpp>
+#include "unit_test.hpp"
+
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+# include <boost/bind.hpp>
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+# include <functional>
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+#if defined(BOOST_ASIO_HAS_BOOST_ARRAY)
+#include <boost/array.hpp>
+#endif // defined(BOOST_ASIO_HAS_BOOST_ARRAY)
+
+#if defined(BOOST_ASIO_HAS_STD_ARRAY)
+# include <array>
+#endif // defined(BOOST_ASIO_HAS_STD_ARRAY)
+
+using namespace std; // For memcmp, memcpy and memset.
+
+class test_stream
+{
+public:
+  typedef boost::asio::io_context::executor_type executor_type;
+
+  test_stream(boost::asio::io_context& io_context)
+    : io_context_(io_context),
+      length_(max_length),
+      position_(0),
+      next_write_length_(max_length)
+  {
+    memset(data_, 0, max_length);
+  }
+
+  executor_type get_executor() BOOST_ASIO_NOEXCEPT
+  {
+    return io_context_.get_executor();
+  }
+
+  void reset(size_t length = max_length)
+  {
+    BOOST_ASIO_CHECK(length <= max_length);
+
+    memset(data_, 0, max_length);
+    length_ = length;
+    position_ = 0;
+    next_write_length_ = length;
+  }
+
+  void next_write_length(size_t length)
+  {
+    next_write_length_ = length;
+  }
+
+  template <typename Iterator>
+  bool check_buffers(Iterator begin, Iterator end, size_t length)
+  {
+    if (length != position_)
+      return false;
+
+    Iterator iter = begin;
+    size_t checked_length = 0;
+    for (; iter != end && checked_length < length; ++iter)
+    {
+      size_t buffer_length = boost::asio::buffer_size(*iter);
+      if (buffer_length > length - checked_length)
+        buffer_length = length - checked_length;
+      if (memcmp(data_ + checked_length, iter->data(), buffer_length) != 0)
+        return false;
+      checked_length += buffer_length;
+    }
+
+    return true;
+  }
+
+  template <typename Const_Buffers>
+  bool check_buffers(const Const_Buffers& buffers, size_t length)
+  {
+    return check_buffers(boost::asio::buffer_sequence_begin(buffers),
+        boost::asio::buffer_sequence_end(buffers), length);
+  }
+
+  template <typename Const_Buffers>
+  size_t write_some(const Const_Buffers& buffers)
+  {
+    size_t n = boost::asio::buffer_copy(
+        boost::asio::buffer(data_, length_) + position_,
+        buffers, next_write_length_);
+    position_ += n;
+    return n;
+  }
+
+  template <typename Const_Buffers>
+  size_t write_some(const Const_Buffers& buffers, boost::system::error_code& ec)
+  {
+    ec = boost::system::error_code();
+    return write_some(buffers);
+  }
+
+  template <typename Const_Buffers, typename Handler>
+  void async_write_some(const Const_Buffers& buffers,
+      BOOST_ASIO_MOVE_ARG(Handler) handler)
+  {
+    size_t bytes_transferred = write_some(buffers);
+    boost::asio::post(get_executor(),
+        boost::asio::detail::bind_handler(
+          BOOST_ASIO_MOVE_CAST(Handler)(handler),
+          boost::system::error_code(), bytes_transferred));
+  }
+
+private:
+  boost::asio::io_context& io_context_;
+  enum { max_length = 8192 };
+  char data_[max_length];
+  size_t length_;
+  size_t position_;
+  size_t next_write_length_;
+};
+
+static const char write_data[]
+  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+static char mutable_write_data[]
+  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+void test_2_arg_zero_buffers_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+
+  size_t bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == 0);
+}
+
+void test_2_arg_const_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  size_t bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_2_arg_mutable_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::mutable_buffer buffers
+    = boost::asio::buffer(mutable_write_data, sizeof(mutable_write_data));
+
+  s.reset();
+  size_t bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+}
+
+void test_2_arg_vector_buffers_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(boost::asio::buffer(write_data, 32));
+  buffers.push_back(boost::asio::buffer(write_data, 39) + 32);
+  buffers.push_back(boost::asio::buffer(write_data) + 39);
+
+  s.reset();
+  size_t bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_2_arg_dynamic_string_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::string data;
+  boost::asio::dynamic_string_buffer<char, std::string::traits_type,
+    std::string::allocator_type> sb
+      = boost::asio::dynamic_buffer(data, sizeof(write_data));
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  size_t bytes_transferred = boost::asio::write(s, sb);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_3_arg_nothrow_zero_buffers_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == 0);
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_3_arg_nothrow_const_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_3_arg_nothrow_mutable_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::mutable_buffer buffers
+    = boost::asio::buffer(mutable_write_data, sizeof(mutable_write_data));
+
+  s.reset();
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_3_arg_nothrow_vector_buffers_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(boost::asio::buffer(write_data, 32));
+  buffers.push_back(boost::asio::buffer(write_data, 39) + 32);
+  buffers.push_back(boost::asio::buffer(write_data) + 39);
+
+  s.reset();
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_3_arg_nothrow_dynamic_string_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::string data;
+  boost::asio::dynamic_string_buffer<char, std::string::traits_type,
+    std::string::allocator_type> sb
+      = boost::asio::dynamic_buffer(data, sizeof(write_data));
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, sb, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+bool old_style_transfer_all(const boost::system::error_code& ec,
+    size_t /*bytes_transferred*/)
+{
+  return !!ec;
+}
+
+struct short_transfer
+{
+  short_transfer() {}
+#if defined(BOOST_ASIO_HAS_MOVE)
+  short_transfer(short_transfer&&) {}
+#else // defined(BOOST_ASIO_HAS_MOVE)
+  short_transfer(const short_transfer&) {}
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+  size_t operator()(const boost::system::error_code& ec,
+      size_t /*bytes_transferred*/)
+  {
+    return !!ec ? 0 : 3;
+  }
+};
+
+void test_3_arg_const_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  size_t bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_3_arg_mutable_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::mutable_buffer buffers
+    = boost::asio::buffer(mutable_write_data, sizeof(mutable_write_data));
+
+  s.reset();
+  size_t bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+}
+
+void test_3_arg_vector_buffers_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(boost::asio::buffer(write_data, 32));
+  buffers.push_back(boost::asio::buffer(write_data, 39) + 32);
+  buffers.push_back(boost::asio::buffer(write_data) + 39);
+
+  s.reset();
+  size_t bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_3_arg_dynamic_string_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::string data;
+  boost::asio::dynamic_string_buffer<char, std::string::traits_type,
+    std::string::allocator_type> sb
+      = boost::asio::dynamic_buffer(data, sizeof(write_data));
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  size_t bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_all());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(1));
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(10));
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(42));
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb, old_style_transfer_all);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  bytes_transferred = boost::asio::write(s, sb, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  bytes_transferred = boost::asio::write(s, sb, short_transfer());
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_4_arg_const_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_4_arg_mutable_buffer_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::mutable_buffer buffers
+    = boost::asio::buffer(mutable_write_data, sizeof(mutable_write_data));
+
+  s.reset();
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(mutable_write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_4_arg_vector_buffers_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(boost::asio::buffer(write_data, 32));
+  buffers.push_back(boost::asio::buffer(write_data, 39) + 32);
+  buffers.push_back(boost::asio::buffer(write_data) + 39);
+
+  s.reset();
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, buffers, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void test_4_arg_dynamic_string_write()
+{
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::string data;
+  boost::asio::dynamic_string_buffer<char, std::string::traits_type,
+    std::string::allocator_type> sb
+      = boost::asio::dynamic_buffer(data, sizeof(write_data));
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  boost::system::error_code error;
+  size_t bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_all(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_at_least(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 50);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(1), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 1);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(10), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 10);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      boost::asio::transfer_exactly(42), error);
+  BOOST_ASIO_CHECK(bytes_transferred == 42);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb,
+      old_style_transfer_all, error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bytes_transferred = boost::asio::write(s, sb, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  error = boost::system::error_code();
+  bytes_transferred = boost::asio::write(s, sb, short_transfer(), error);
+  BOOST_ASIO_CHECK(bytes_transferred == sizeof(write_data));
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+  BOOST_ASIO_CHECK(!error);
+}
+
+void async_write_handler(const boost::system::error_code& e,
+    size_t bytes_transferred, size_t expected_bytes_transferred, bool* called)
+{
+  *called = true;
+  BOOST_ASIO_CHECK(!e);
+  BOOST_ASIO_CHECK(bytes_transferred == expected_bytes_transferred);
+}
+
+void test_3_arg_const_buffer_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_3_arg_mutable_buffer_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::mutable_buffer buffers
+    = boost::asio::buffer(mutable_write_data, sizeof(mutable_write_data));
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+}
+
+void test_3_arg_boost_array_buffers_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+#if defined(BOOST_ASIO_HAS_BOOST_ARRAY)
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::array<boost::asio::const_buffer, 2> buffers = { {
+    boost::asio::buffer(write_data, 32),
+    boost::asio::buffer(write_data) + 32 } };
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+#endif // defined(BOOST_ASIO_HAS_BOOST_ARRAY)
+}
+
+void test_3_arg_std_array_buffers_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+#if defined(BOOST_ASIO_HAS_STD_ARRAY)
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::array<boost::asio::const_buffer, 2> buffers = { {
+    boost::asio::buffer(write_data, 32),
+    boost::asio::buffer(write_data) + 32 } };
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+#endif // defined(BOOST_ASIO_HAS_STD_ARRAY)
+}
+
+void test_3_arg_vector_buffers_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(boost::asio::buffer(write_data, 32));
+  buffers.push_back(boost::asio::buffer(write_data, 39) + 32);
+  buffers.push_back(boost::asio::buffer(write_data) + 39);
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_3_arg_dynamic_string_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::string data;
+  boost::asio::dynamic_string_buffer<char, std::string::traits_type,
+    std::string::allocator_type> sb
+      = boost::asio::dynamic_buffer(data, sizeof(write_data));
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bool called = false;
+  boost::asio::async_write(s, sb,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  int i = boost::asio::async_write(s, sb, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_3_arg_streambuf_async_write()
+{
+#if !defined(BOOST_ASIO_NO_DYNAMIC_BUFFER_V1)
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::streambuf sb;
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  bool called = false;
+  boost::asio::async_write(s, sb,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  int i = boost::asio::async_write(s, sb, archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+#endif // !defined(BOOST_ASIO_NO_DYNAMIC_BUFFER_V1)
+}
+
+void test_4_arg_const_buffer_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_4_arg_mutable_buffer_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::mutable_buffer buffers
+    = boost::asio::buffer(mutable_write_data, sizeof(mutable_write_data));
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(mutable_write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(mutable_write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_4_arg_boost_array_buffers_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+#if defined(BOOST_ASIO_HAS_BOOST_ARRAY)
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::array<boost::asio::const_buffer, 2> buffers = { {
+    boost::asio::buffer(write_data, 32),
+    boost::asio::buffer(write_data) + 32 } };
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+#endif // defined(BOOST_ASIO_HAS_BOOST_ARRAY)
+}
+
+void test_4_arg_std_array_buffers_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+#if defined(BOOST_ASIO_HAS_STD_ARRAY)
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::array<boost::asio::const_buffer, 2> buffers = { {
+    boost::asio::buffer(write_data, 32),
+    boost::asio::buffer(write_data) + 32 } };
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+#endif // defined(BOOST_ASIO_HAS_STD_ARRAY)
+}
+
+void test_4_arg_vector_buffers_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::vector<boost::asio::const_buffer> buffers;
+  buffers.push_back(boost::asio::buffer(write_data, 32));
+  buffers.push_back(boost::asio::buffer(write_data, 39) + 32);
+  buffers.push_back(boost::asio::buffer(write_data) + 39);
+
+  s.reset();
+  bool called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, buffers, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  int i = boost::asio::async_write(s, buffers, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_4_arg_dynamic_string_async_write()
+{
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  std::string data;
+  boost::asio::dynamic_string_buffer<char, std::string::traits_type,
+    std::string::allocator_type> sb
+      = boost::asio::dynamic_buffer(data, sizeof(write_data));
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  bool called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  data.assign(write_data, sizeof(write_data));
+  int i = boost::asio::async_write(s, sb, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+}
+
+void test_4_arg_streambuf_async_write()
+{
+#if !defined(BOOST_ASIO_NO_DYNAMIC_BUFFER_V1)
+#if defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = boost;
+#else // defined(BOOST_ASIO_HAS_BOOST_BIND)
+  namespace bindns = std;
+  using std::placeholders::_1;
+  using std::placeholders::_2;
+#endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
+
+  boost::asio::io_context ioc;
+  test_stream s(ioc);
+  boost::asio::streambuf sb;
+  boost::asio::const_buffer buffers
+    = boost::asio::buffer(write_data, sizeof(write_data));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  bool called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_all(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_at_least(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 50, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 50));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(1),
+      bindns::bind(async_write_handler,
+        _1, _2, 1, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 1));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(10),
+      bindns::bind(async_write_handler,
+        _1, _2, 10, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 10));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, boost::asio::transfer_exactly(42),
+      bindns::bind(async_write_handler,
+        _1, _2, 42, &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, 42));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, old_style_transfer_all,
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  called = false;
+  boost::asio::async_write(s, sb, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(1);
+  called = false;
+  boost::asio::async_write(s, sb, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  s.next_write_length(10);
+  called = false;
+  boost::asio::async_write(s, sb, short_transfer(),
+      bindns::bind(async_write_handler,
+        _1, _2, sizeof(write_data), &called));
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(called);
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+
+  s.reset();
+  sb.consume(sb.size());
+  sb.sputn(write_data, sizeof(write_data));
+  int i = boost::asio::async_write(s, sb, short_transfer(),
+      archetypes::lazy_handler());
+  BOOST_ASIO_CHECK(i == 42);
+  ioc.restart();
+  ioc.run();
+  BOOST_ASIO_CHECK(s.check_buffers(buffers, sizeof(write_data)));
+#endif // !defined(BOOST_ASIO_NO_DYNAMIC_BUFFER_V1)
+}
+
+BOOST_ASIO_TEST_SUITE
+(
+  "write",
+  BOOST_ASIO_TEST_CASE(test_2_arg_zero_buffers_write)
+  BOOST_ASIO_TEST_CASE(test_2_arg_const_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_2_arg_mutable_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_2_arg_vector_buffers_write)
+  BOOST_ASIO_TEST_CASE(test_2_arg_dynamic_string_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_nothrow_zero_buffers_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_nothrow_const_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_nothrow_mutable_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_nothrow_vector_buffers_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_nothrow_dynamic_string_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_const_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_mutable_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_vector_buffers_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_dynamic_string_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_const_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_mutable_buffer_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_vector_buffers_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_dynamic_string_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_const_buffer_async_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_mutable_buffer_async_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_boost_array_buffers_async_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_std_array_buffers_async_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_vector_buffers_async_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_dynamic_string_async_write)
+  BOOST_ASIO_TEST_CASE(test_3_arg_streambuf_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_const_buffer_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_mutable_buffer_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_boost_array_buffers_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_std_array_buffers_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_vector_buffers_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_dynamic_string_async_write)
+  BOOST_ASIO_TEST_CASE(test_4_arg_streambuf_async_write)
+)